1-5 Please explain in detail the expected noise levels that will be generated during (a) normal operations, (b) startup operations, (c) normal shut down operations, (d) steam releases, and (e) emergency shut down operations. Please provide details for both natural gas operations and fuel oil operations. Please identify the models used to project the noise levels during each such phase of operations (a) through (e).
1-8 Please explain whether the facility will be able to maintain compliance with the Town’s overall 43 dBA noise limit (applicable at the nearest houses) during all non-emergency operating conditions, including most importantly, normal startups and shut downs.
1-10 Does Invenergy, or its parent or related company, operate another combined cycle plant that uses an air cooled condenser (ACC)? If so, please identify the plant and the noise mitigation installations in each such plant.
1-11 Do you agree that the noise generated during the steam turbine bypass phase of startup—when high pressure steam is injected directly into the vacuum of the main duct of the ACC is going to be extremely loud if no mitigation efforts are made? Please provide details.
2-1 Table 1 on Page 7 of Appendix A (“Transient Operation Noise Level Evaluation for the Clear River Energy Center”, Michael Theriault Acoustics, Inc., March 2016) contains the expected near field sound pressure levels at various points along the air cooled condenser (ACC) duct during steam turbine bypass. Could you please explain the source or derivation of the values specifically associated with the following sources:
- ACC Main Horizontal Ducts
- ACC Riser Ducts
- ACC Finger Ducts
- HRH Steam Bypass Ducts
- LP Steam Bypass Ducts
2-6 The noise modeling analysis suggests that the best sound level that can be realized at Receptor M1 during a normal start-up is 46 dBA. Does that mean that Invenergy believes that compliance with the overall 43 dBA Town Ordinance (neglecting the octave band component) cannot be achieved?